Eotaby-drill head



H. e. JOHNSTON.

ROTARY DRILL HEAD. APPLICATION FILED AUG-6. I919.

' Patented July 27 1920.

J wow 04,

UNITED STATES PATENT OFFICE.

HORACE G. JoHNs'roN, or consronm, rEXAsAssIeNoR TO GENEVIEVE JOHNSTON,

1 i i or CORSICANA, rEXAs. r

Specification of Letters Patent.

Eo'rAnYmnILL HEAD.

Patented July 2?, 1920.

Application filed August 6, 1919. Serial No. 315,776.

To all whom it may concern:

Be it known that I, Henson G. JOHNSTON, a citizenof the United States,residing at Corsicana, in the county of Navarro and State of Texas, haveinvented certain new and useful Improvements in Rotary-Drill Heads; andI do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

This invention relates to drill apparatus and more particularly to thattype of apparatus in which drill rods of cruciform cross section arerotated while being sunk.

It is one of the objects of the present invention to improve the headgear or driving mechanism of drill apparatus and espe cially to providefor the efficient driving of the apparatus and yet enable the freevertical movement of the drill rod or driving shank.

With this and other objects in view, as will become readily manifest tothose versed in the art, the invention consists in the means and indetails and arrangement of the parts as more particularly described inthe following specification relative to the embodiment of the inventionshown in the accompanying drawing, wherein:

Figure 1 is a plan View of my improved driving head clamp.

Fig. 2 is a vertical section on a line 2-2 of Fig. 1.

Fig. 3 is a plan view of the head as mounted upon the turn table, and

Fig. 4: is a side elevation partially in section on a line 4t of Fig. 3.

The present apparatus is of that type in volving a suitably rotated andhorizontal table 2 driven by any suitable means, indicated here asincluding a pinion 3 engaging a complementary gear 4, formed or securedon the turn-table 2.

This turn-table is provided with'a central bore or chamber in whichthere is mounted a removable bushing 5 which is free to rotate on aledge 5 on the turn-table and having lugs 6 which engage the under sideof the ledge on the interior surface of the turntable 2.

On top of the turntable are provided suitable bosses 8 cast integralwith the turntable on which are arranged suitable transverse fasteningbars or cleats 10. The bosses 8 engage with recesses formed at the outerend of the clamp structure 13-13 imparting rotary motion to the clamp.

An important feature of the present invention resides in the improvementof a clamp and the mounting of the same in the bushing or ring 5 and, ashere shown, this ring is provided with a conical bore 11 complementaryto the tapering body 12 of a clamp consisting of two substantiallyduplicate and interchangeable members 13 and 13 which may be clampedtogether by transversely extending bolts 14.

This clamp constitutes, therefore, a split socket having a centrallongitudinal aperture 15, the transverse contour of which approximatesthe contour of the drill rod or shank that may be extended down throughthe head structure, such shank usually being longitudinally fluted or ofcruciform cross section, so that its shoulders will interlock with theshoulders of the socket 15 and rotary motion therefore be imparted bythe clamp to the drill rod or shank.

This rotary motion is transmitted in the present case from the drivingdogs or bosses 8 which project into recesses formed in the outer end ofthe clamp structure 13-13 and indicated at 16.

By the present construction the conical body part 12 of the clampstructure is designed to allow the bushing to rotate on it and alsowithin the turn-table as may be necessary in the exigencies ofoperation, although the ring and the clamp may have a general rotationdue to the rotation of the turn-table 2 which carries the driving meansconnecting the drill shank or rod to the driving head for rotation.

Having thus described my invention, what I clalm is:

1. In a rotary drill operating mechanism,

a turn-table having a central opening, a

bushing rotatably mounted concentrically of said table, a clamp engagingmeans on the turn-table, a divided clamp adapted to be engaged by saidclamp engaging means on the table, and means on the bushing for engagingsaid divided clamp to keep the same from spreading.

2. In a rotary drill operating mechanism, a turn-table having a centralopening, a bushing rotatably seated in said opening and provided withmeans for preventing unseating thereof, a clamp engaging means on theturn-table, a divided drill clamp adapted to be engaged by said clampengaging means on the table, and cooperating means on sa1d bushing andclamp to prevent said clamp from spreading.

3; In a rotary drill head, a turn-table,

removable bushing free to rotate on a seat on the turn-tableand having aconical seat,

and a clamp removably -mounted on the seat and having a tapered bodyportion com? v ends; lugs ,onthe turn-table to enter said movement ofthe clamp and lugs.

'ends for driving purposes; and retaining means for preventing verticalor separating 5; In a rotary drill head, a turn-table and itsdrivingmechanism; a removable drill receiving and driving clamp loosely mountedupon the turn-table, and having bifurcated ends; lugs on the turn-tableto enter said ends for driving purposes; and retaining means forpreventing vertical or separating movement of the clamp and lugs, saidlast named means comprising transverse cleats secured to the lugs andoverhanging the clamp ends.

Intestimony whereofI aflix my signature.

HORACE Gr. JOHNSTON.

